Iran's supreme leader says world powers must lift international sanctions and not merely suspend them as part of a landmark nuclear agreement.

Speaking to a group of clerics, Ayatollah Ali Khamenei said "there will be no deal" if the sanctions are not lifted. His remarks were read by a state TV anchorman.

Khamenei says some US officials have spoken of the "suspension" of the sanctions, which he says is unacceptable. He says Iran will only partially comply with its commitments if the sanctions are merely suspended.

US President Barack Obama recently secured enough support to prevent the Republican-led Congress from blocking the deal.

The agreement would curb Iran's nuclear activities in return for sanctions relief.